The newly-redeveloped multi-purpose stadium would be used by the Robins and Bristol Rugby, both of whom are overseen by the same umbrella company, Bristol Sport
The club's spiritual home in South Bristol would be redeveloped in stages over time to incorporate new stands to replace the existing Wedlock and Williams stands which, together with renovation works, would increase the capacity to over 26,000 seats.
The proposed redevelopment is estimated to cost £40million, with any shortfall being underwritten by Bristol Sport owner Steve Lansdown.
Jon Lansdown, speaking on behalf of the City board said: "Ashton Gate has been the club's spiritual home for more than 100 years and these plans would improve and enhance the facilities ready for the next 100 years.
"The stadium would be designed with supporters in mind; there would be full engagement and consultation to ensure we represent the history and heritage of the club as fans would like.
"Modern stadium facilities are a key pillar for the club, closely aligned with our community engagement and the importance of financial prudence. This redevelopment plan is testament to all of that."
This redevelopment plan is an alternative should the club fail in their bid to build a new 30,000 all-seater stadium in the nearby Ashton Vale.
"These plans give us a viable alternative to Ashton Vale," Lansdown added. "The landowners of Ashton Vale remain very confident that they will be successful at the Inquiry in October, but we need to make sure we have an alternative as, regardless of where it is sited, the club needs a new stadium."
Plans will be submitted early in the summer months and, once underway, a full stadium redevelopment would be deliverable within three years.